Gevork B. Gharehpetian

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—In this paper, a new topology for cascaded multilevel converter based on submultilevel converter units and full-bridge converters is proposed. The proposed topology significantly reduces the number of dc voltage sources, switches, IGBTs, and power diodes as the number of output voltage levels increases. Also, an algorithm to determine dc voltage sources(More)
A microgrid (MG) comprises a low-voltage network with several microsources, critical and noncritical loads, and energy storage systems (ESSs). It can operate in the grid-connected or islanded modes. In islanded mode, the voltage and frequency of the MG should be controlled by different distributed energy resources (DERs). This paper focuses on the analysis(More)
This paper presents an effective method to control distributed energy resources (DERs) installed in a microgrid (MG) to guarantee its stability after islanding occurrence. Considering voltage and frequency variations after islanding occurrence and based on stability criteria, MG pre-islanding conditions are divided into secure and insecure classes. It is(More)
This paper presents the transient model of a new FACTS device, the center node unified power flow controller(C-UPFC), installed at the midpoint of a transmission line. The C-UPFC consists of three voltage source inverters (VSI) with common DC link. One of the converters is connected in parallel at the midpoint of line and the other two converters are(More)